Garage Roof Rafter Size

Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.

Garage roof rafter size.

Rafter length using angle v r 2cos a rafter length using pitch v r 2 sqrt 1 p 2 where v overhang r roof span p pitch. Our roof rafter calculator tools are handy for calculating the number of rafters needed rafter length calculator lineal feet of rafter board feed in ridge and sub facia and the total board feet in the roof. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. The most common rafter spacing is 24 inches and 5 8 inch plywood is recommended for that.

If your local building authority has a rafter spacing code you may not space rafters wider than required by code. Maximum clear span of rafters in metres for roof pitches of between 15 and 45 degrees roof pitch between 15 and 22 5 degrees with rafter spacing strength class c16 size of rafters in mm. Structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes. Just enter the dimensions of the roof rise and run to get started.

Surveyors and structural engineers utilise data from tables below to help calculate the correct size strength and centres of roof timbers for the required spans and loadings. For rafters spaced 20 or more inches apart 1 2 or 5 8 inch plywood is recommended. Offset rafter framing can be done on garage roof framing if you are building a garage from plans that are sealed by a professional architect or structural engineer licensed within the jurisdiction you are building a garage in if those designs specify rafter offset. For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2.

It is always better to have a large rafter rather than be concerned with a sagging roof. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches. Use our online rafter length calculator to quickly compute the length of the shed roof rafter by entering the measurements of overhead length of roof span pitch or angle. For pitched roofs flat roofs and ceiling joists.

The closer the rafters are to each other the stronger the roof will be. Surveyors span tables for designing roof rafters.